U.S. Pat. Nos. 7,476,135 and 7,329,162, which are incorporated herein by reference, disclose cooling systems for a marine vessel, which are configured to allow all cooling water to flow out of the cooling circuit naturally and under the influence of gravity when the marine vessel is removed from the body of water. All conduits of the cooling circuit are sloped downwardly and rearwardly from within the marine vessel to an opening through its transom. Traps are avoided so that residual water is not retained within locations of the cooling system after the natural draining process is complete. The opening through the transom of the marine vessel is at or below all conduits of the cooling system in order to facilitate the natural draining of the cooling system under the influence of gravity and without the need for operator intervention.
U.S. Pat. No. 7,585,196 which is incorporated herein by reference discloses a cooling system for a marine propulsion device that provides a transom opening that is sufficiently low with respect to other components of the marine propulsion device to allow automatic draining of all cooling water from the system when the marine vessel is removed from the body of water in which it had been operating. The engine cooling passages and other conduits and passages of the cooling system are all located at positions above the transom opening. The system provides automatic draining for a marine cooling system that is an open system and which contains no closed cooling portions.
U.S. Pat. No. 7,114,469, which is incorporated herein by reference discloses a cooling system for a marine engine which divides a flow of cooling water into first and second streams downstream of a pump. The first stream flows through a first cooling system which is controlled by a pressure sensitive valve. The second stream flows through a second cooling system which is controlled by a temperature sensitive valve.
U.S. Pat. No. 6,821,171, which is incorporated herein by reference discloses a cooling system for a marine engine which conducts water from a coolant pump through the cylinder head and exhaust conduit prior to conducting the cooling water through the cylinder block. This raises the temperature of the water prior to its entering the cooling passages of the cylinder block.
U.S. Pat. No. 6,135,064 which is incorporated herein by reference discloses an engine cooling system is provided with a manifold that is located below the lowest point of the cooling system of an engine. The manifold is connected to the cooling system of the engine, a water pump, a circulation pump, the exhaust manifolds of the engine, and a drain conduit through which all of the water can be drained from the engine.
U.S. Pat. No. 6,390,870 which is incorporated herein by reference discloses a draining system for a marine propulsion engine which is provided in which a manifold is located at a low portion of the cooling system to allow all of the water within the cooling system to drain through a common location, or manifold. A rigid shaft is connected to a valve associated with the manifold and extended upwardly from the manifold to a location proximate the upper portion of the engine so that a marine vessel operator can easily reach the upper end of the shaft and manipulate the shaft to open the valve of the manifold. In this way, the valve can be opened to allow all of the water to drain from the engine without requiring the marine vessel operator to reach toward locations at the bottom portion of the engine.
U.S. Pat. No. 6,379,201 which is incorporated herein by reference discloses a marine engine cooling system provided with a valve in which a ball moves freely within a cavity formed within the valve. Pressurized water, from a sea pump, causes the ball to block fluid flow through the cavity and forces pumped water to flow through a preferred conduit which may include a heat exchanger. When the sea pump is inoperative, the ball moves downward within the cavity to unblock a drain passage and allow water to drain from the heat generating components of the marine engine.
U.S. Pat. No. 4,897,059 which is incorporated herein by reference, discloses a corrosion resistant coolant pump for placement in the cooling system of a marine drive, which includes a corrosion resistant member mounted to and rotatable with a drive shaft interconnected with and rotatable in response to the engine crankshaft. The corrosion resistant member is preferably a cup adapted for receiving and enclosing an end of the drive shaft, with a portion of the cup extending into a cavity formed in the coolant pump housing. The cavity is in communication with marine drive cooling system. An impeller is connected to the cup and housed within the cavity for pumping coolant through the system. The cup is interconnected with the drive shaft so as to be rotatable in response thereto, thereby driving the impeller in response to rotation of the drive shaft. A sealing mechanism is provided about the cup for sealing the cavity and preventing contact of coolant with the drive shaft. With this construction, a carbon steel drive shaft can be utilized in a salt water coolant environment, thereby eliminating the need for constructing the entire drive shaft of a corrosion resistant material.
U.S. Pat. No. 4,741,715 which is incorporated herein by reference discloses a pressure actuated drain valve for automatically draining the cooling water from a marine drive engine when the engine is stopped. The drain valve includes a spring-loaded diaphragm which moves to a closed position when the engine water pump is operating to close an outlet from the engine cavities to be drained. The diaphragm automatically moves to its open position when the engine water pump is off to open the outlet to allow cooling water to drain from the engine cavities.
U.S. Pat. No. 4,728,306 which is incorporated herein by reference discloses a marine propulsion auxiliary cooling system is provided by an electric auxiliary water pump pumping sea water to cool the engine and/or fuel line after turn off of the engine to prevent vaporization of the fuel, or in response to another given engine condition.
U.S. Pat. No. 4,392,779 which is incorporated herein by reference discloses marine drives having water cooled engines utilize a water pump mounted over the drive shaft and internal to the drive shaft housing to provide engine cooling, the pump having stamped metal housing parts and a flexible impeller.